Very new to WordPress

Hello Everyone:
We had a person that was developing our site using WordPress and now he has left the company. I was in process of being trained on how to use WordPress.
I was on vacation when this person left and found out that the site was taking off-line (ie it was on-line for testing) and the files were moved to a folder called Site.
We stated to add images to the pages but we got a flag. The uploaded file could not be moved to .